More answers

we need to get +17 using 3*1 and factors of 10 - try 5 * 2
by inspection you can see that 3 * 5 + 1 * 2 will do it
so put 3 and 5 on 'outside' and 1 and 2 on inside
(3x + 2)(1x + 5)

TuringTest

6 years ago

I start with (3x+_)(x+_), since you must have at least that to get the 3x^{2}, then just figure which two numbers multiply to give 10 and add to give 17. hence 5 and 2, just make sure to put them in the right place! (check after)